libc-top-half/musl/src/unistd/isatty.c

   1 #include <unistd.h>
   2 #include <errno.h>
   3 #include <sys/ioctl.h>
   4 #include "syscall.h"
   5
   6 int isatty(int fd)
   7 {
   8         struct winsize wsz;
   9         unsigned long r = syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz);
  10         if (r == 0) return 1;
  11         if (errno != EBADF) errno = ENOTTY;
  12         return 0;
  13 }